What it means
An option is a right without an obligation, and exercising is the moment you take up that right. Until you exercise you hold a contract; afterwards you hold the shares, the commodity or the cash settlement the contract pointed at.
In employee share schemes, exercising means paying the strike price (the fixed price set when the option was granted) and receiving shares in return. Nobody exercises for fun: it costs real money and it usually triggers a tax event, so the timing matters as much as the decision itself.
The economics are simple. You exercise when the market price sits above the strike price, because the difference, called the spread or the intrinsic value, is what you gain, and if the market price sits below the strike then the option is out of the money and letting it lapse costs nothing.
Style matters too. American style options can be exercised at any point up to expiry while European style options can only be exercised on the expiry date itself, and most listed equity options are American style even though index options frequently are not.
Exercising early is usually a mistake for tradeable options because it throws away time value, the extra amount an option is worth simply because there is still time for the price to move. Selling the option normally captures more than exercising it, which is why traders close positions far more often than they exercise them.
In practice
Real-world examples.
Example
A software engineer at a listed payments company holds options at a $6.00 strike while the shares trade at $19.00. She exercises 5,000 of them, paying $30,000 and receiving shares worth $95,000, and holds the rest back so the tax lands across two financial years.
Example
A commodities trader at a food manufacturer holds call options on wheat that are deep in the money three days before expiry. Rather than exercise and take delivery of grain the mill cannot store, he sells the contracts and buys physical wheat from his usual supplier.
Example
A departing sales director at a private logistics firm has 90 days to exercise vested options after leaving. The shares are illiquid, so exercising would mean paying $85,000 in cash plus a tax bill on paper gains he cannot sell, and he lets most of the options lapse.
Formula
Calculation
Intrinsic value per share = market price - strike price
Cost to exercise = strike price x number of options
Total spread on exercise = (market price - strike price) x number of options
An employee holds 20,000 share options with a strike price of $8.00, and the shares now trade at $23.50. Exercising costs 20,000 x $8.00 = $160,000 in cash, and the shares received are worth 20,000 x $23.50 = $470,000.
The spread is therefore $470,000 - $160,000 = $310,000, which is the same as 20,000 x ($23.50 - $8.00) = $310,000. If that spread is taxed as employment income at a combined 40% rate, the tax bill is $310,000 x 0.40 = $124,000, leaving $186,000 of value before any later capital gain on the shares themselves.Case study
Seen in the real world.
The following is an illustrative and entirely fictional example. Marlow Quay Diagnostics, an invented laboratory equipment maker, granted its operations lead 60,000 options at a strike price of $2.50 during an early funding round. Seven years later the company listed, the shares settled at $12.00, and the options were three months from expiry.
Exercising outright would have cost 60,000 x $2.50 = $150,000 in cash, which she did not have. Her broker offered a cashless exercise: sell just enough of the new shares to cover the strike cost, which at $12.00 a share meant $150,000 / $12.00 = 12,500 shares.
That left her with 60,000 - 12,500 = 47,500 shares worth 47,500 x $12.00 = $570,000, matching the spread of 60,000 x ($12.00 - $2.50) = $570,000 exactly. In this fictional case the trade-off was clear: she gave up 12,500 shares of future upside in exchange for never having to find $150,000 of her own money.
Watch out
Common mistakes.
- Exercising options as soon as they vest, which often means paying tax early on a gain that has not yet been turned into cash.
- Confusing exercising with vesting, when vesting is the point at which the right becomes yours to use and exercising is the point at which you use it.
- Exercising a tradeable option instead of selling it, which throws away the time value still left in the contract.
Questions
People also ask.
What happens if I never exercise an option that is in the money?
Most brokers exercise listed contracts automatically at expiry, but company share schemes usually do not, so an unexercised option simply lapses and is worth nothing.
Do I need cash to exercise?
Usually yes, though cashless exercise, where some of the new shares are sold immediately to fund the strike price and the tax, is common once the shares are liquid.
Is exercising the same as assignment?
No, assignment is the mirror image, because the seller of the option is the one required to deliver when the buyer chooses to exercise.
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